


perception

by Anonymous



Category: Ao no Exorcist | Blue Exorcist
Genre: Gen, gratuitous headcanons, im a manga reader
Language: English
Status: Completed
Published: 2020-12-08
Updated: 2020-12-08
Packaged: 2021-03-10 03:13:43
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,019
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27947354
Author URL: https://archiveofourown.org/
Summary: Yukio was nine years old when he learned he was half-demon.
Comments: 2
Kudos: 37
Collections: Anonymous





	perception

**Author's Note:**

> yukio lives in my brain and has given me at least 4 mental illnesses i think (one of them is actually writing fanfic because thats just something i dont do)
> 
> ft my headcanon that he has littel fangs cause i think he deserves them.

Yukio was nine years old when he learned he was half-demon.

Two years beforehand, his father had finally reassured him that the monsters he had been seeing all his life were real. He had been told he could learn to defend himself from the monsters, but that his brother could not know. The reason, Shiro said at the time, was because Rin could not see the demons, and he needed to be protected. At seven, Yukio had accepted this explanation, but as his training began and his knowledge grew, he began asking himself more questions. It occurred to him that he had no idea why he and Shiro could see the demons, but Rin could not.

At the end of one of his one-on-one lessons with Shiro, he finally brought this up.

“Father, why is it that we can see the demons, but Nii-san can’t?” Yukio’s tone was hesitant. This was a burning question, but he was afraid of the answer.

Shiro leaned back and sighed. “I knew you were gonna ask eventually,” he said.

Yukio leaned forward, trying to swallow the lump in his throat.

“This has to do with who your real parents are,” Shiro began slowly. Yukio was taken aback.

“I thought you didn’t know who they were,” Yukio said.

“Yeah, that was a lie,” Shiro said roughly. “You, and Rin, were born of a human woman and the king of all demons, Satan. But,” he continued, seeing Yukio’s pale face, “you two are fraternal twins. Rin inherited Satan’s power, and you were born human.”

“I… Nii-san is…” Yukio was at a loss for words. He averted his eyes. Shiro put a comforting hand on his shoulder.

“The reason you can see demons, and he can’t, is because he gave you a mashou when you were born. The power he inherited from Satan was sealed away, in a sword called Kurikara. He is completely unaware of the existence of demons.”

“So when you told me… I could protect Nii-san…” Yukio had tears in his eyes, but he wiped them away before they could fall.

Shiro sighed. “He is going to be a target of both exorcists and demons alike. That’s the truth of it.”

Yukio abruptly stood. “I’ll… I’ll get stronger,” he said. “I’ll protect Nii-san.” He noticed his father’s concerned expression, but turned away and headed towards his room.

The snores of his brother punctuated his thoughts as he lay in his bed, facing the wall. He scrunched up his face, but didn’t let himself cry. Crying was for the weak, and he wasn’t going to be weak anymore. But the information he had been given tonight was still a lot to process.

He found himself unable to sleep that night. The thoughts his brain supplied him with, far more concerning than what typical nine-year-olds had to grapple with, kept him awake despite his exhaustion.

_I can’t believe I have to keep all of this from Nii-san._

_What if I’m not strong enough to protect him?_

_If my brother is a demon, and my blood father is the king of demons, what does that make me?_

* * *

Despite his father’s reassurance that he was human, Yukio found himself running his tongue across his teeth and glancing at his fingernails to make sure they were still rounded, still human. They always had been, of course. He surreptitiously glanced at his brother, as well, but he appeared fully human, like he always had been. There was no reason to suspect he could be the son of the king of all demons.

But once he noticed it for the first time, he couldn’t stop noticing the red glint of his eyes in the mirror.

He noticed it in Rin’s eyes, too. But no one else’s.

Yukio wondered about the fact that darkness was supposed to make things hard to see. It had scared him when he was younger, but that was more because that was where the demons lurked, following him with their eyes. He had always maintained some kind of vision when there was no light. He was starting to think it wasn’t normal.

Yukio made eye contact with a cat in a dark alleyway. He held its eerie, glowing gaze for a long time before it hissed and darted around a corner. He wondered what  the cat’s eyes saw when they stared into his own.

* * *

His adult canine had grown in a little longer than the baby tooth he had lost. That was fine. It was normal to have a little bit of variation from the norm. It’s not like one longer (and sharper) tooth would mean much.

All four of his new canine  teeth came in like that. Rin’s did, too.

No one said anything. It was fine.

* * *

W hen other exorcists referred only to Rin as the bastard son of Satan, Yukio didn’t correct them. It was safer to play along, and Yukio didn’t want to worry about himself on top of everything else. Rin was the one who inherited the blue flames. Rin was the one who was  _dangerous_ .

The thought of Rin’s impending execution was not one Yukio liked to entertain. He couldn’t bear the idea that in less than a year, his only family could very well be executed simply for existing. Yet in the time he knew he had, he couldn’t treat Rin like his family at all. He was his  lazy, slacking  student, and a demon that had to be controlled, and Yukio had too much  work  on his plate to spend  any more  time with him. Despite his best efforts, Yukio felt the weight of a crushing loneliness, that he bitterly realized was  ultimately the result of him being the more  _human_ twin.

He shoved the feeling deep down into the primordial soup of emotions in his heart, and hated himself more for it.

Shura had said that his pent-up emotions could turn someone into a demon.

When he stared into the mirror, past his completely normal features and into the faint red of his pupils and his tiny little vampire fangs, he  already felt like a failed demon.

**Author's Note:**

> i just needed to get this out there thank u for reading <3


End file.
